Define a new variable in the file in C. More...

Functions
int	PIOc_def_var (int ncid, const char name, nc_type xtype, int ndims, const int dimidsp, int *varidp)
	The PIO-C interface for the NetCDF function nc_def_var. More...

int	PIOc_def_var_fill (int ncid, int varid, int fill_mode, const void *fill_valuep)
	Set the fill value for a variable. More...

int	PIOc_def_var_deflate (int ncid, int varid, int shuffle, int deflate, int deflate_level)
	Set deflate (zlib) settings for a variable. More...

int	PIOc_def_var_chunking (int ncid, int varid, int storage, const PIO_Offset *chunksizesp)
	Set chunksizes for a variable. More...

int	PIOc_def_var_endian (int ncid, int varid, int endian)
	Set chunksizes for a variable. More...

int	PIOc_set_chunk_cache (int iosysid, int iotype, PIO_Offset size, PIO_Offset nelems, float preemption)
	Set chunk cache netCDF files to be opened/created. More...

int	PIOc_get_chunk_cache (int iosysid, int iotype, PIO_Offset sizep, PIO_Offset nelemsp, float *preemptionp)
	Get current file chunk cache settings from HDF5. More...

int	PIOc_set_var_chunk_cache (int ncid, int varid, PIO_Offset size, PIO_Offset nelems, float preemption)
	Set chunksizes for a variable. More...

Detailed Description

Define a new variable in the file in C.

Function Documentation

◆ PIOc_def_var()

int PIOc_def_var	(	int	ncid,
		const char *	name,
		nc_type	xtype,
		int	ndims,
		const int *	dimidsp,
		int *	varidp
	)

The PIO-C interface for the NetCDF function nc_def_var.

This routine is called collectively by all tasks in the communicator ios.union_comm. For more information on the underlying NetCDF commmand please read about this function in the NetCDF documentation at: http://www.unidata.ucar.edu/software/netcdf/docs/group__variables.html

Parameters

ncid	the ncid of the open file, obtained from PIOc_openfile() or PIOc_createfile().
name	the variable name.
xtype	the PIO_TYPE of the variable.
ndims	the number of dimensions.
dimidsp	pointer to array of dimension IDs.
varidp	a pointer that will get the variable ID.

Returns: PIO_NOERR for success, error code otherwise.

Author: Jim Edwards, Ed Hartnett

◆ PIOc_def_var_chunking()

int PIOc_def_var_chunking	(	int	ncid,
		int	varid,
		int	storage,
		const PIO_Offset *	chunksizesp
	)

Set chunksizes for a variable.

This function only applies to netCDF-4 files. When used with netCDF classic files, the error PIO_ENOTNC4 will be returned.

Chunksizes have important performance repercussions. NetCDF attempts to choose sensible chunk sizes by default, but for best performance check chunking against access patterns.

See the netCDF variable documentation for details about the operation of this function.

Parameters

ncid	the ncid of the open file.
varid	the ID of the variable to set chunksizes for.
storage	NC_CONTIGUOUS or NC_CHUNKED.
chunksizesp	an array of chunksizes. Must have a chunksize for every variable dimension.

Returns: PIO_NOERR for success, otherwise an error code.

Author: Ed Hartnett

◆ PIOc_def_var_deflate()

int PIOc_def_var_deflate	(	int	ncid,
		int	varid,
		int	shuffle,
		int	deflate,
		int	deflate_level
	)

Set deflate (zlib) settings for a variable.

This function only applies to netCDF-4 files. When used with netCDF classic files, the error PIO_ENOTNC4 will be returned.

See the netCDF variable documentation for details about the operation of this function.

Parameters

ncid	the ncid of the open file.
varid	the ID of the variable.
shuffle	non-zero to turn on shuffle filter.
deflate	non-zero to turn on zlib compression for this variable.
deflate_level	1 to 9, with 1 being faster and 9 being more compressed.

Returns: PIO_NOERR for success, otherwise an error code.

Author: Ed Hartnett

◆ PIOc_def_var_endian()

int PIOc_def_var_endian	(	int	ncid,
		int	varid,
		int	endian
	)

Set chunksizes for a variable.

This function only applies to netCDF-4 files. When used with netCDF classic files, the error PIO_ENOTNC4 will be returned.

See the netCDF variable documentation for details about the operation of this function.

Chunksizes have important performance repercussions. NetCDF attempts to choose sensible chunk sizes by default, but for best performance check chunking against access patterns.

Parameters

ncid	the ncid of the open file.
varid	the ID of the variable to set chunksizes for.
endian	NC_ENDIAN_NATIVE, NC_ENDIAN_LITTLE, or NC_ENDIAN_BIG.

Returns: PIO_NOERR for success, otherwise an error code.

Author: Ed Hartnett

◆ PIOc_def_var_fill()

int PIOc_def_var_fill	(	int	ncid,
		int	varid,
		int	fill_mode,
		const void *	fill_valuep
	)

Set the fill value for a variable.

See the netCDF variable documentation for details about the operation of this function.

When the fill mode for the file is NC_FILL, then fill values are used for missing data. This function sets the fill value to be used for a variable. If no specific fill value is set (as a _FillValue attribute), then the default fill values from netcdf.h are used.

NetCDF-4 and pnetcdf files allow setting fill_mode (to NC_FILL or NC_NOFILL) on a per-variable basis. NetCDF classic only allows the fill_mode setting to be set for the whole file. For this function, the fill_mode parameter is ignored for classic files. Set the file-level fill mode with PIOc_set_fill().

Parameters

ncid	the ncid of the open file.
varid	the ID of the variable to set chunksizes for.
fill_mode	fill mode for this variable (NC_FILL or NC_NOFILL)
fill_valuep	pointer to the fill value to be used if fill_mode is set to NC_FILL.

Returns: PIO_NOERR for success, otherwise an error code.

Author: Jim Edwards, Ed Hartnett

◆ PIOc_get_chunk_cache()

int PIOc_get_chunk_cache	(	int	iosysid,
		int	iotype,
		PIO_Offset *	sizep,
		PIO_Offset *	nelemsp,
		float *	preemptionp
	)

Get current file chunk cache settings from HDF5.

This function has no effect on netCDF classic files. Calling this function with iotype of PIO_IOTYPE_PNETCDF or PIO_IOTYPE_NETCDF returns an error.

The file chunk cache for HDF5 can be set, and will apply for any files opened or created until the program ends, or the settings are changed again. The cache settings apply only to the open file. They do not persist with the file, and must be set each time the file is opened, before it is opened, if they are to have effect.

See the netCDF variable documentation for details about the operation of this function.

Chunksizes have important performance repercussions. NetCDF attempts to choose sensible chunk sizes by default, but for best performance check chunking against access patterns.

Parameters

iosysid	the IO system ID.
iotype	the iotype of files to be created or opened.
sizep	gets the size of file cache.
nelemsp	gets the number of elements in file cache.
preemptionp	gets the preemption setting for file cache.

Returns: PIO_NOERR for success, otherwise an error code.

Author: Ed Hartnett

◆ PIOc_set_chunk_cache()

int PIOc_set_chunk_cache	(	int	iosysid,
		int	iotype,
		PIO_Offset	size,
		PIO_Offset	nelems,
		float	preemption
	)

Set chunk cache netCDF files to be opened/created.

This function only applies to netCDF-4 files. When used with netCDF classic files, the error PIO_ENOTNC4 will be returned.

The file chunk cache for HDF5 can be set, and will apply for any files opened or created until the program ends, or the settings are changed again. The cache settings apply only to the open file. They do not persist with the file, and must be set each time the file is opened, before it is opened, if they are to have effect.

See the netCDF variable documentation for details about the operation of this function.

Parameters

iosysid	the IO system ID.
iotype	the iotype of files to be created or opened.
size	size of file cache.
nelems	number of elements in file cache.
preemption	preemption setting for file cache.

Returns: PIO_NOERR for success, otherwise an error code.

Author: Ed Hartnett

◆ PIOc_set_var_chunk_cache()

int PIOc_set_var_chunk_cache	(	int	ncid,
		int	varid,
		PIO_Offset	size,
		PIO_Offset	nelems,
		float	preemption
	)

Set chunksizes for a variable.

This function only applies to netCDF-4 files. When used with netCDF classic files, the error PIO_ENOTNC4 will be returned.

See the netCDF variable documentation for details about the operation of this function.

Chunksizes have important performance repercussions. NetCDF attempts to choose sensible chunk sizes by default, but for best performance check chunking against access patterns.

Parameters

ncid	the ncid of the open file.
varid	the ID of the variable to set chunksizes for.
size	the size in bytes for the cache.
nelems	the number of elements in the cache.
preemption	the cache preemption value.

Returns: PIO_NOERR for success, otherwise an error code.

Author: Ed Hartnett

Functions

Detailed Description

Function Documentation

◆ PIOc_def_var()

◆ PIOc_def_var_chunking()

◆ PIOc_def_var_deflate()

◆ PIOc_def_var_endian()

◆ PIOc_def_var_fill()

◆ PIOc_get_chunk_cache()

◆ PIOc_set_chunk_cache()

◆ PIOc_set_var_chunk_cache()